Testing system for telephone-lines.



W. W. DEAN.

TESTING SYSTEM FOR TELEPHONE LINES.

APPLICATION FILED JUNE 29, 1903.

916,1 17. Patented Mar. 23, 1909.

UNITED STATES PATENT OFFICE.

WILLIAM W. DEAN, OF CHICAGOfILLIN OIS, ASSIGNOR TO KELLOGG SWITGIIBOARD & SUPPLY COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION 01 ILLINOIS.

TESTING SYSTEM FOR TELEPHONE-LINES.

Specification of Letters Patent.

Patented March 2.3, 1909.

Application filed June 29, 1903. Serial No. 163,614.

T o'oll whom "it may concern:

Be it known that I, WILLIAM W. DEAN, a citizen of the United States of America, and resident of .Chicago, county of Cook, and State of Illinois, have invented a new and useful Improvement in Testing Systems for Telephone-Lines, of which the following is a specification.

My invention relates to im rovements in testing systems for telephone lines, and consists in means whereby the test relay of the system is normally separated or, isolated from the operators connective means, whereby'in case of the short circuiting of one or more of the cords or connective means, or if there is general leakage in all of the said means at some particular operators the said test relay is not derange In -my application filed June 29th, 1903, Serial No. 163,613, I show and describe 'meansfor thus accomplishing the isolation of the testing device in which the testin for conversation when the connection is established with the called line. In my present arrangement l do not sever the said strand of the'cord circuit, but I open normally the connection of said strand with ound or common return and connect therewith the test devicepreferably through contacts of'the listening key.

Other features of the invention are brought out iii the detailed description and claims.

subscribers manent bridge of the line conductors,

' and J My invention is illustratedin the accom panying drawing in which- Figure 1', is a diagram of atelephone system embodying my improvements, and Fig. 2 is a diagram of a modification of same.

Referring to Fig. 1, L and L indicate two lines extendingin two limbs 2 and 3 from their respective substations to the central office. At each substation a call.

hell 4 and a condenser 5 are located in a pic;

w la

a transmitter 6 and a receiver 7 are included in another bridge which is normally open at the switch-hook 8.

At the central office each line is fitted as usual with a line si nal S and an answerim jack J and a lura ity of multiple jacks 5 The inc conductor 2 is normally grounded, but is adapted during conversaosition, v and is adapted-for proper operation with any of the switchboard cords or operators connective means that is in proper working condition.

' swering end The said test relay tion to be connected with the tip conductor of the jack SGCLIOII oi the line; while the sleeve conductor 3 of the telephone line is normally connected with the common conductor 9 or 9 extending to the live pole oi the common battery B or B. These line conductors include the winding of the line relay R which controls the local circuit of the line signal S. The cut-ofi' relay It has its winding connected to'ground from the sleeve conductor of the jack section of the tele one line.

T e operators cord circuit comprises an answering plug 1: and a calling plug P hav-' ing tip and sleeve contacts adapted to register with the corresponding contacts of the spring jacks of the lines when the plugs are inserted therein. The tip contacts of the said plugs are connected together by the flexible strands t and t and the interposed condenser a, while the sleeve contacts of said plugs are joined by the similar strands s and s? and the interposed condenser 0 The supervisory relays r and r are connected across the anof the cord circuit upon the oposite sides of the battery B and control the coal circuit of the supervisory signal S associated with the answering plug. A similar pair of supervisory relays r and 1" are together with the battery B associated nith the calling end of the cord circuit, the relay 1" being directly connected between the live pole of said battery B and the sleeve strand .9 while the tip rela T has its connection betweenthe tip stran t and the grounded pole of the battery B" completed through normally open contacts 10 of the said sleeve relay 1". These relays together control the local circuit of the supervisory lamp S associated with the calling plug P. hi h impedance test relay P, which is preferably common to allof the cord circuits at each operators position, is connected betv. een ground and the movable contact 11 of the tip relay 1' by conductor 12, the normal contact 13 of said movable contact being joined by the conductor 14 with a norma y open contact of the tip listening key spring 15. r is therefore normally separated'or isolated from the strands of the cord circuit, but when the listening key It is 0 rated to connect the operators setwith t e cord circuit, said relay is thereby connected with the-tip strand t of the cord c1rcuit, This operators seteomprisesa head The high resistance and t telephone 16, an induction coil 17 and a condenser 18, which are adapted to be connected in a bridge of the cord circuit by the listening key springs 15, the operators transmitter 19 being charged from any suitable current source. operated to complete a path for current from battery B over conductor 9 and through conductor 20 including the third winding 21 of the operator's induction coil. A ringing generator 23 is adapted to be connected with the tip strandt of the cord circuit v. hen the ringing key sprin s 24 are operated, the forward portion of t e sleeve strand beingconlin'e, tests-the line in the usual manner to de- The optermine its idle or busy condition. eration of her listening key automatically completes the test relay circuit. If the line is idle the test rings thereof are connected with ground through the cut-off relay R and since the tip of the testing plug is likewise connected with ground through the said test. re-

lay no flow of current results and no click is received. The operator is thus made aware of the fact that the line is idle. If the line is busy, however, the said test rings are connected with the live pole of one of the batteries B or B and a path for current is com- "pleted over the said tip. strand t the tip spring 15 of the listening key, conductor 14,

contacts 13 and 11 of the tipsupervisory relay r conductor 12 and the high resistance and hi h impedance test relay 1 to ground. This re ay is adjusted to respondto the flow of current over this path, and attracts its armature to thereby close the path for current through the tertiary winding 21 of the o erators induction coil. The closing of t is path therefore causes a click in the operators receiver, and indicates to her that the line is bus Assuming that the line is found idle, the callin plug P is inserted in one of the multiple acks of the line, and the ringing key 24 is operated to connect the calling genera ator 23 in circuit. During ringing current flows from the battery B over conductors 9 and '25, and through the cut oif relay of the called line to maintain thesame 0 erated. After the subscriber has been ca led and before his responsathe sleeve super viso relay 1* is'operated to close the loqal 'CllGllli) of the supervisorysignal S which is The test relay 1* is adapted when lighted to indicate the fact that the subscriber has not yet responded. Said relay 1' also closes the path for current through the .tip strand i, so that when the subscriber versation the test relay is not again connected therewith and the talking circuit is not opened. During conversation the batteries B and B are furnishing current over the telephone lines for the operation of the substation transmitters, while the voice currents are inductively transmitted from one line to the other through the condensers c and c in the cord circuit strands. At the termination of the conversation when the subscribers return their receivers to the hooks, current is cut off from the tip superyisory relays r and r 'which are deenergized to close the local circuits of the supervisory signals. These signals are therefore lighted to indicate to the operator that the conversation has terminated when the connection may be taken down and all parts returned to normal condition. It is thus seen that the test relay is normally disconnected from the operators cord circuit and if a general leakage should exist in the cord circuits, or if one of thecord circuits should become short circuited, the test relay is not operated thereby. The cord circuits that are not so disabled may therefore be used with the test relay in the ordinary manner.

Fig. 2 shows a similar arrangement except that a conductor 30 extends from the back contact of spring 10 of relay e to normally open contacts of the listening key 15 and these are joined by conductor 31 with the ungrounded terminal of the test relay 1' What I claim is:

1. In a telephone system, the combination with acord circuit having a com lete testing strand, of a test relay norma ly isolated therefrom, a test indicating device con.- trolled by said relay, a listening keyfor' connecting s'aid relay with said strand during testing, and a supervisory relay for automatically disconnecting said relay. from said strand during conversation, substantially as. described.

2; In a telephone'testingsystem, the com bination with a cord circuit having a com plete testing strand, of a test relay normally isolated therefrom and: from theopera'tors listenin set, a test indicating device controlled y said -relay, and means for manu-' ally connecting said relay and said set with h 7 said strand during testing and further means for preventing the connection of said relay during conversation, substantially as deisolated therefrom, a test indicating device controlled by said relay, a listening key to connect said relay with said strand during testing, said relay being independent of the operators listening set, and a supervisory relay associated with the cord circuit for automatically disconnecting said test relay from said strand during conversation. I

4, In a telephone testing system,-the combination with a cord circuit having a com.-

lete testing strand, of a test relay normally isolated therefrom, a test indicating device controlled by said relay, and means for connecting said relay with said strand during testing and electromagnetic means for disconnecting said relay during conversation,

substantially as described.

5. 'In a telephone testing system, the combination with a cord circuit having a comlete testing strand, of a test relay normally isolated therefrom, a test indicating device controlled by said relay, means for connecting said relay with said strand for testing,

and a supervisory relay associated with the cord circuit for automatically disconnecting it during conversation, substantially as described.

f 6. In a telephone testing system, the combination with a cord circuit having a comlete testing strand, of a test relay normally isolated therefrom, a test indicating device controlled by.said relay, means for connecting said relay with said strand for testing, and electro-magnetic means for completely disconnecting said relay? from said testing strand during conversatipn, substantially as described. i

7: In a telephone testing system, the combination with'a connecting plug. and a busy testing strand associated therewith, a test relay, said relay being independent of the operators. listening set, means for manually connecting said relay with theterminal of said plug and at the same time leaving the tip talking strand intact, a test responsive device controlled by. the relay, and means actuated during conversation for disconnectin the saidrelay, substantially as describe I 8. In a telephone testin -system, the combination with a connecting plug and thestrands associated therewith, of a test" relay and a responsive device controlled thereby, means for normally connecting said relayv with one terminal of the plug and at the f same time leaving the talking strand associated with said terminal. intact, and an electro-magnetic device controlled by current over one strand for disconnecting said relay during conversation, substantially as described.

9. In a telephone testing system, the combination with tale hope lines having testing contacts connected directly with one side of the talking circiiit during conversation, of an operatorfs cqnnective circuit having its talking strands permanently completed so far as the testing apparatus is concerned, a central source of current associated'with the lines for talking purposes, a testing apparatus comprising it testing terminal to cooperate with one oft said cdntacts in testing, a high resistance and test} iresponsive device in circuit with sai 5 terminal, and means to automatically remove thel same upon the connection of the d erators connective circuit with the line, su stantizilly as described.

'10. In a telephone testing system, the combination with telephone lines-having testing contacts connected directly withone side of the talking circuit during conversation, of an operators connective circuit having normally complete talkingstrands, a cen-. tral source of current associated with the lines, said source being used for talking purposes, testing apparatus comprising a testing terminal to cooperate with one of said contacts, a test responsive device in circuit with said terminal, the test circuit .being of high resistance-and impedance to prevent a large or sudden variation on the line when tested, a supervisory relay associated with said testing terminal but normally disconnected therefrom, andmeans to automatically cut out such resistance and to connect saidsu-f peiwisory relay with the said terminal during conversation, substantially as described.

11. In a-telephone testing system, the combination with telephone lines having testing contacts connected directly with one side of the talking circuit during a connection, of an operators connective circuit to furnish current for talking purposes associated with the lines, a testing apparatus. comprising a testing terminal to cooperate with the said testin contacts of the' lines, said testing terminal eing normally connect! ed with a complete talking strand, a highrepervisory relay associated With the strand of the operators connective circuit connected with said test terminal but normally disconnected therefrom, and a relay operated over the other strand of the cord circuit actuated during a conversation to remove said resistance and connect-said relay to its circuit, substantially. as described.

12, In a telephone 1 testing system, the

combination with telephone lines having testing contacts therefor connected directly, .with one side ofithe-talking circuits during conversation, .of a plurality of operators connective circuits, and a central source of current associated therewith and adapted to furnish current for talking purposes, testing ing circuit when the operators connective circuits are in use for conversation and to phone line circuit provided with one or more spring jack switches or connection terminals, one or each of said switches being provided with a testing contact, said testing contact being connected to one side of the talking circuit of said line when switched for conversation, an operators connective circuit having complete talking strands terminating at one end in a plug provided with contact terminals adapted to register with the contacts of said spring jack switches, and at the other end in a plug provided with contact termi nals adapted to register with the contacts of a calling line, a'source of current associated with said cord circuit and adapted to furnish current for talking for said line when switched for conversation, a supervisory signal associated with saidcordcircuit and adapted to be operated when connection is made with a line, and a relay for rendering said signal inoperative controlled by a switch at the distant end of the linecircuit, said switch serving to allow the flow of current over said line, a test responsive device associated with said cord circuit and operated over a circuit of relatively high resistance, said circuit being completed between the testing contact of the test plug and the testing contact of said line terminal when the line is tested for conversation, an electro-magnetic device associated with said cord circuit and controlling the circuit of said supervisory signal at one point and adapted to operate during conversation and to complete the circuit for said super visory relay, and means to disconnect said test receiving circuit during conversation a second supervisory relay for the cord cir cuit actuated when the line is closed at the substation, a normally complete tip strand for said cord circuit, a test responsive device connected therewith for testing, and contacts of the first supervisory relay normally isolating the second supervisory relay from the testing strand of the cord circuit, where-- by the testing current will not be shunted away from said test responsive device, substantially as described.

15. In a telephone system, the combination with telephone lines, each having a test terminal, of a cord circuit to connect said lines for conversation, said cord circuit having a normally complete up strand so faras conversation is concerned, a supervisory signal for the'cord circuit, a supervisory relay actuated when a connection is made with a telephone line to display said signal,

a second supervisory relay actuated when, the line is closed at the substation to efiace to furnish energizing current to the line, a test responsive device connected with the tip strand of the cord circuit for testing and contacts of-the first supervisory relay nor-' mally isolating the second supervisory relay from the tip strand of the cord circuit, whereby the testing current will not be shunted away from said responsive device, substantially as described.

said signal, the latter relay being adapted 16. In a telephone system, the combination with a cord circuit having a complete tip strand, a supervisory relay having its coil connected therewith during conversation, a test receiving device connected with said tip strand for testin the coil of said supervisory relay being (isconnected from said tip strand during as described.

17. In a telephone system, ,the combination with a cord circuit, of a condenser dividing a strand of said cordcircu'it into two parts, one of saidparts forming a testtesting, substantially ing conductor, a source of current, an impedance coil connected between said source and said testing conductor during conversa- State of Illinois, this 12th day of June 1903.

WILLIAM W. DEAN. v

Witnesses:

ROBERT LEWIS AMEs, EVA A. GARLOQK. 

